Timeline: do not rely on UpdateLayer & PaintLayer trace events

Source/core/inspector/InspectorTimelineAgent.h

 /*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
@@ skipping 150 matching lines @@
     void didLayout(RenderObject*);
 
     void willAutosizeText(RenderObject*);
     void didAutosizeText(RenderObject*);
 
     void didScheduleStyleRecalculation(Document*);
     bool willRecalculateStyle(Document*);
     void didRecalculateStyle();
     void didRecalculateStyleForElement();
 
-    void willPaint(RenderObject*);
+    void willPaint(RenderObject*, const GraphicsLayer*);
     void didPaint(RenderObject*, const GraphicsLayer*, GraphicsContext*, const LayoutRect&);
 
     void willPaintImage(RenderImage*);
     void didPaintImage();
 
     void willScrollLayer(RenderObject*);
     void didScrollLayer();
 
     void willComposite();
     void didComposite();
@@ skipping 91 matching lines @@
 
     void commitFrameRecord();
 
     void addRecordToTimeline(PassRefPtr<JSONObject>);
     void innerAddRecordToTimeline(PassRefPtr<JSONObject>);
     void clearRecordStack();
 
     void localToPageQuad(const RenderObject& renderer, const LayoutRect&, FloatQuad*);
     const TimelineTimeConverter& timeConverter() const { return m_timeConverter; }
     const RenderImage* imageBeingPainted() const { return m_imageBeingPainted; }
+    int nodeBeingPainted() const { return m_nodeBeingPainted; }
+    int layerBeingPainted() const { return m_layerBeingPainted; }
     long long nodeId(Node*);
     long long nodeId(RenderObject*);
     void releaseNodeIds();
 
     double timestamp();
     Page* page();
 
     bool isStarted();
     void innerStart();
     void innerStop(bool fromConsole);
@@ skipping 24 matching lines @@
     unsigned m_platformInstrumentationClientInstalledAtStackDepth;
     RefPtr<JSONObject> m_pendingFrameRecord;
     RefPtr<JSONObject> m_pendingGPURecord;
     InspectorType m_inspectorType;
     InspectorClient* m_client;
     WeakPtrFactory<InspectorTimelineAgent> m_weakFactory;
     RefPtr<TimelineTraceEventProcessor> m_traceEventProcessor;
     unsigned m_styleRecalcElementCounter;
     int m_layerTreeId;
     RenderImage* m_imageBeingPainted;
+    int m_nodeBeingPainted;
+    int m_layerBeingPainted;
     Vector<String> m_consoleTimelines;
     RefPtr<TypeBuilder::Array<TypeBuilder::Timeline::TimelineEvent> > m_bufferedEvents;
     InspectorOverlay* m_overlay;
 };
 
 } // namespace WebCore
 
 #endif // !defined(InspectorTimelineAgent_h)